The present exemplary embodiments relate to signal housings. They find particular application in conjunction with housing multiple LED groups within an automotive, railway, vehicular, waterway, illumination, and/or pedestrian signal. One particular application for such a signal is to substitute three separate and distinct LED groups each in its own housing into a single integrated tri-color signal within one housing. However, it is to be appreciated that the present exemplary embodiment is also amenable to other like applications.
Automotive, railway, vehicular, waterway, illumination, and/or pedestrian signals are employed to regulate motorists and pedestrians via various commands. These commands are provided by various illuminated elements with particular colors and/or shapes that are each associated with an instruction. Elements are conventionally illuminated via incandescent bulbs which use heat caused by an electrical current to emit light. When electrical current passes through a filament (e.g., tungsten), it causes the filament to heat to the point that it glows and gives off light. Such illumination can be covered with a colored lens and/or template to provide a meaningful instruction that can be viewed in a variety of external lighting conditions.
The filament is a resistive element in the incandescent bulb circuit. The amount of current drawn by the filament is proportional to its impedance. This impedance value increases as the temperature of the filament increases. Thus, a conventional lamp has a larger initial current draw which drops in proportion to the increase in the filament impedance. This variation in current draw is known and a predetermined range can be utilized to monitor the lamp operation. As such, a lamp failure condition can be identified based on the amount of current drawn by the filament. In one example, the filament fails (e.g., breaks) causing the impedance approaches an infinite value and the current value decreases to almost zero. If the current drawn is outside of the predetermined range, a responsive action can be initiated by a current monitor or other control system.
Unlike incandescent-based signals, LED-based signals consist of an array of LED elements, which draw much less power. LED-based signals have numerous advantages over incandescent signals, such as greater energy efficiency and a longer lifetime between replacements than conventional signals. However, there are some drawbacks related to current LED signal designs. Three LED signals are generally employed to replace conventional incandescent signals on a one-to-one basis. In addition, current multiple color LED signals are susceptible to color mixing failure due to poor insulation design.
What are needed are systems and methods to provide multi-color signal designs with a single integrated signal that is consolidated into one housing.